The Southern Right Whale has for some time been widely accepted as a species separate from its northern hemisphere relatives, although Rice (1998) regarded the right whales in all oceans as a single species (and placed them in the genus Balaena along with B. mysticetus, the Bowhead Whale). Recent genetic analyses support the concept of three separate phylogenetic species of right whale, one in the North Atlantic, one in the North Pacific, and one in the southern hemisphere (Rosenbaum et al. 2000). The International Whaling Commission (IWC) Scientific Committee (IWC 2004) and the Convention on Migratory Species accept the latter taxonomy. The ranges of the three species do not overlap.

Justification:
Given the recent estimated population size (1,600 mature females in 1997, and approximately twice that number in 2007) and the strong observed rate of increase in some well-studied parts of the range, the species, although still scarce relative to its historic abundance, is not considered under threat at the hemispheric level. The population is estimated to be higher now than it was three generations (87 years, assuming a generation time of 29 years; Taylor et al. 2007) ago. Some breeding populations, in particular that off Chile/Peru (see separate listing), are still very small and may need special protection to become re-established.

Southern right whales have a circumpolar distribution in the Southern Hemisphere. The distribution in winter, at least of the breeding component of the population, is concentrated near coastlines in the northern part of the range. Major current breeding areas are nearshore off southern Australia, New Zealand (particularly Auckland Islands and Campbell Islands), Atlantic coast of South America (Argentina and Brazil), and southern Africa (mainly South Africa). Small numbers are also seen off central Chile, Peru, Tristan da Cunha (British Overseas Territory), and the east coast of Madagascar (IWC 2001, Rosenbaum et al. 2001). In summer right whales are found mainly in latitudes 40-50°S (Ohsumi and Kasamatsu 1986) but have been seen, especially in recent years, in the Antarctic as far south as 65°S (IWC 2007, Bannister et al. 1999) and around South Georgia (Rowntree et al. 2001).

The map shows where the species may occur based on oceanography. The species has not been recorded for all the states within the hypothetical range as shown on the map. States for which confirmed records of the species exist are included in the list of native range states.

The IWC conducted its last major review of southern right whales in 1998 (IWC 2001), from which most of this information is taken.

Following severe historical depletion by commercial whaling, several breeding populations (Argentina/Brazil, South Africa, and Australia) of southern right whales (E. australis) have shown evidence of strong recovery, with a doubling time of 10-12 years (Bannister 2001, Best et al. 2001, Cooke et al. 2001). The other breeding populations are still very small, and data are insufficient to determine whether they are recovering. Estimated total population size as of 1997 was 7,500 animals (of which 1,600 were mature females, including 547 from Argentina and 659 from South Africa), and the three main populations have continued to increase at a similar rate since then (Best et al. 2005, Cooke et al. 2003, IWC 2007). Illegal Soviet catches (mainly in the 1960s) temporarily inhibited recovery, but overall the population appears to have grown strongly since then (see below).

There appears to be substantial interchange between breeding grounds off the same continent, e.g. between Argentina and Brazil (Groch et al. 2004), but a much smaller rate of interchange between land masses, e.g. between Australia and New Zealand (Anon. 2004) and Argentina and Tristan da Cunha (Best et al. 1993).

Southern right whales have been well-studied on their winter breeding grounds, especially at Peninsula Valdés, Argentina, and in Australia and South Africa. Researchers have used callosity patterns to identify individuals on these grounds, and have learned much about the southern right whale's behavior, communication, and reproduction. Females produce calves at 3-5 year intervals, usually three years but with a lengthening of the cycle to five years when feeding conditions are poor (Leaper et al. 2006). Calves are born from June to October with a peak in August after a 12-13 month gestation period (Best 1994). Where feeding occurs north of 40°S the diet consists mainly of copepods, south of 50°S mainly euphausiids (krill), and varying proportions of the two food items at intermediate latitudes (Tormosov et al. 1998).

Southern right whales were hunted extensively by pre-modern whaling starting in the early 17th century, but especially in the 18th and 19th centuries by American and European whalers. Not all records have survived, and furthermore there is uncertainty over the numbers of animals killed but not caught. The total number processed between 1770 and 1900 is conservatively estimated at about 150,000, of which 48,000-60,000 were taken in the 1830s alone. By the start of modern whaling at the beginning of the 20th century, the species was already rare, and catches thereafter until right whales were legally protected in 1935 totalled only about 1,600 individuals. Over 3,000 were taken illegally by Soviet whaling fleets in the 1960s (Tormosov et al. 1998). The hemispheric population in 1770 is estimated at 55,000-70,000 and is estimated to have been depleted to a low of about 300 animals by the 1920s. The species presumably began to recover following protection in 1935, but the illegal Soviet catches in the 1960s are estimated to have removed over half of the remaining population and delayed recovery (IWC 2001).

Like their congeners in the Northern Hemisphere, southern right whales are subject to mortality due to entanglements in fishing gear and collisions with shipping (IWC 2001). However, this does not seem to have impeded their recovery, at least in some areas. The lower average density of human populations and thus fishing, shipping and other potentially harmful activities in the Southern Hemisphere, compared with the western North Atlantic, probably makes this species less affected by such activities than is the North Atlantic right whale.

Parasitism by kelp gulls Larus dominicanus, which gouge skin and blubber from the whales’ backs, has been increasing rapidly in the Península Valdés calving ground and may eventually drive the whales elsewhere (Rowntree et al. 1998). This appears to be a learned behaviour that has spread through the gull population, and which is likely exacerbated by the elevated gull populations provisioned by the prevalence of uncovered disposal sites for fishery and other waste.

Observed correlations between breeding success off Argentina and sea surface temperature anomalies at South Georgia suggest that as Antarctic feeding grounds warm up, the average calving rate of southern right whales can be expected to decline (Leaper et al. 2006).

Right whales have been protected internationally from commercial hunting since 1935, but this has only been fully respected since the early 1970s, when the presence of international observers ended illegal catches by Soviet fleets, and land stations in South America also stopped taking right whales. Although several countries have designated marine protected areas that include right whale breeding habitat, it is not always clear what additional level of protection is offered over and above that applying to whales in the country’s waters generally. Those protected areas with specific management measures aimed at protecting the right whales in their calving grounds include the Area de Proteção Ambiental de Baleia Franca (Right Whale Environmental Protection Area) off Catarina State in Brazil, the Golfo San José Provincial Marine Park (Parque Marino Golfo San José) in Argentina, and the Great Australian Bight Marine Park in South Australia.